The invention regards a method of operating a programmable sewing machine, an automat or the like, as well as a drive and control apparatus for performing the method.
DE-OS 37 22 962 discloses a method for operating a programmable sewing machine in which a specific program type is selected prior to inputting the sewing machine functions and prior to inputting one of the available sequences of program parts within each program type. The operator then additionally inputs different sewing parameters, e.g. the number of stitches per seam.
In the prior art, seams or seam lengths are defined by the connection of two points on a material to be sewn and are obtained by sewn stitches. While the number of stitches of the seams can be selected by the operator, the sequence in which the seams are concatenated is preprogrammed. Moreover it is possible to predefine specific events which occur as a function of the seam or of the sewing of the stitches. For example, a time with a preselected duration can elapse after the end of a seam with a preselected number of stitches. During the time e.g. the sewn part is conveyed away from the sewing machine and stacked. For this purpose the sewing machine control device has different outputs, which can be activated as a function of the seam or the number of stitches. Thus, for example, an output can be provided, which is switched in during a number of stitches programmed by the operator at the start of the seam, another output is switched in for a time programmed by the operator after stopping the needle at the end of the seam or an output is switched in throughout the entire seam length.
However, such control devices suffer from the disadvantage that, due to the way the sequence is programmed, the operator cannot associate a random output with a random seam or seam length. It is also not possible to switch in an output for a specific or non-specific time at a random point in the sewing sequence, or to insert or non-specific waiting time at a random point in the sewing machine sequence. This means that a given sequence of the sewing process is predetermined in a fixed manner and the parameters of number of stitches or time can only be modified within this fixed sequence.
Moreover it is not possible to make the execution of a seam or a time in the sewing process dependent on events that might occur during any arbitrary point or time of the sewing process.
The problem posed to the invention is therefore to provide a method for operating a sewing machine and an apparatus for controlling the same, which permits a greater flexibility in the working sequence, which inter alia leads to a time saving.